Black disazo dye and process of making same.



UNITED STATES Patented December 27, 1904.

PATENT OEEIcE.

KARL SOHIRMAOHER, OF HOOHST-ON-THE-MAIN, GERMANY, ASSTGNOR TOFARBlVERKE, VORM. MEISTER, LUCIUS & BRUNING, OF HOOHST- ON-THE-NIAIN,GERMANY, A CORPORATION OF GERMANY.

BLACK DISAZO DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 778,610, dated December27, 1904.

' Application filed July 30, 1904. Serial No. 218,891. ($pecimens.)

To all whom, it may concern:

Be it known that I, KARL ScHIRMAoHnR, Ph. D., chemist, acitizen oftheEmpire of Germany, residing at HGchst-on-the-Main, Ger- 5 many, haveinvented certain new and useful Improvements in Black Disazo Dyes andProcesses of Making Same, of which the following is a specification.

A meta-phenylenediamindisulfonic acid is I described in the GermanLetters Patent N 0.

78,82. There it is said that it may be diazotized and tetrazotized; butit is not mentioned in which manner. Ihave found that only under certainconditions said meta-phenylenedi- I amindisulfonic acid can betetrazotized without simultaneously producing avesuvin coloring-matter,and the resulting product is not, as might be expected, thetetrazobenzoldisulfonic acid corresponding to the phenylenedi- 2Oamindisulfonic acid, but a new tetrazophenosulfonic acid. In order toavoid the formation of the vesuvin dyestulf and in order to get a goodyield of the tetrazophenosulfonic acid, a larger quantity of nitrite isused than 5 is required for normal tetrazotizing.

By the combination of the new tetrazophenolsulfonic acid withbeta-naphthol a disazo dye is produced which dyes wool a red-brownshade. The latter is converted into a 'fast 3 black by a subsequenttreatment with chromates.

The process may be carried out, for instance, as follows: 26.8 kilos ofmeta-phenylenediamindisulfonic acid are dissolved in water to a solutionof four to five per cent. with 10.7 kilos of soda, and seventeen kilosof nitrite are added. This solution is slowly introduced at ordinarytemperature below the surface of a mixture of eighty kilos ofhydrochloric acid 4 of 20 Baum specific gravity and four hundred litersof water. The solution at first of a light-yellow appearance becomesslightly darker toward the end of the introduction and thetetrazophenolsulfonic' acid separates assmall yellow crystals.Partlyitremainsdissolved. After one hours stirring the transformation isfinished. The tetrazophenolsulfonic acid obtained from 26.8 kilos ofmetaphenylenediamindisulfonic acid is gradually run into a solution of20 centigrade of 29.2 5

kilos of beta-naphthol, eighty kilos of causticsoda lye of 40 specificgravity,and thirty kilos of sodium carbonate. After some time themixture is slowly heated to 40 to centigrade, and this temperature ismaintained for 55 from three to four hours. The dyestuff separates. Tofilter it easily, common salt is added. When cold, it is filtered andwashed with a solution of common salt. When dry, the dyestuif is a darkpowder of bronze luster, 6O soluble in hot water to a bluish-violetcolor. On addition of much water it turns to red in consequence ofdissociation. It also turns to red on addition of acid and brownish-redflakes separate. The dyestuff dyes wool a 5 brownish-red shade whichbecomes black on subsequent treatment with chromates.

Having now described my invention, what I claim is 1. The process ofproducing a black disazo 7 dyestuff which consists in tetrazotizing theknown sulfonic acid of meta-phenylenediamin with an excess of nitriteand then combining the thus-formed tetrazophenolsulfonic acid withbeta-naphthol.

2. As anew product the disazo dye obtained by combining thetetrazophenolsulfonic acid resulting from meta-phenylenediamindisulfonicacid with beta-naphthol; the dyestuif is a dark powder of bronze luster,soluble in hot water to a bluish-violet color, on addition of acid thiscolor turns to red and brownish-red flakes are separated; it directlydyes wool a red-brown shade which becomes black on subsequent treatmentwith chromates. 5

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing witnesses.

KARL SOHIRMAOHER. W itnesses:

J OHANN HARKENSTEIN, BERNHARD LEYDECKER.

